Cutting tools employing a resilient clamping mechanism for clamping cutting inserts are generally of relatively narrow thickness, typically in the range of 0.5 mm to 12 mm and the cutting insert is retained in an insert pocket located between the clamping surfaces of upper and lower jaws of the cutting tool. In cutting operations such as grooving and parting off the cutting tool is in the form of a holder blade. The holder blade is, in turn, generally clamped in a blade-retaining block. The holder blade is generally provided with a suitably designed opening, in the vicinity of the insert pocket whereby a relatively narrow bridging portion is formed enabling a limited degree of resilient displacement of one of the holder blade's jaws relative to the other. Generally, the lower jaw is rigid and the upper jaw is resiliently displaceable. The opening can be of the form of an aperture, or a slot, or a slot terminating in an aperture. Examples of such cutting tools are disclosed in U.S. Pat. Nos. 3,785,021, 4,580,930 and 5,829,924. A rotary slot-cutting tool employing a resilient insert clamping mechanism is disclosed in U.S. Pat. No. 4,417,833. The cutter body is disc-shaped and of relatively narrow thickness, with cutting insert pockets located around its periphery. As with the holder blade, an insert pocket of a rotary slot-cutting tool has two jaws between which an insert is clamped by means of the resilient force resulting from the displacement of the clamping jaw.
Whether the cutting tool is a holder blade or a rotary slot cutting tool, the displacement of the clamping jaw is obtained by manufacturing the insert pocket so that the distance between the clamping surfaces of the jaws is smaller than the height of the portion of the insert located between the clamping surfaces. Consequently, when an insert is located in the insert pocket, the clamping jaw is held in a displaced position creating an elastic force by means of which the insert is clamped in position.
A well-known problem with cutting tools of the type described above is that the cutting insert is not positively secured in the insert pocket and therefore can become dislodged during cutting operations. For example, this can happen during grooving operations when attempting to withdraw the holder blade from a workpiece. In some cases the cutting insert can be completely pulled out of the holder blade and become embedded in the workpiece. This problem can be especially troubling with rotary slot-cutting tools where the cutting insert can even fly out of the insert pocket under the influence of centrifugal forces, a situation that can be particularly dangerous when operating at high speeds.